The present invention relates to adjustable lever load binders which are used to tension a length of chain securing a load during transportation.
The prior art includes various devices which are used for securing heavy cargo that has been loaded on open top railcars, trailers, and containers. The term “open top” refers to freight cars, intermodal trailers, and containers that are not enclosed—and thus potentially expose the cargo to the environment. Vehicles in this category include various types of flat cars, gondola cars, hopper cars, flatbed trailers, flat rack containers, among others.
Chain tiedown assemblies are often used to secure heavy cargo in all three directions—longitudinal, lateral, and vertical. To ensure that the load does not move or shift, restraint values must be observed per the rules utilized in that particular transportation industry. For example, typical restraint requirements for rail road transportation are: longitudinal direction—three times the weight from each side of the load; lateral direction—two times the weight from each side of the load; and vertical direction—two times the weight.
The prior art includes three types of load binders for use in securement of open top loads—ratchet type, turnbuckle type, and lever type. As will be recognized by those skilled in the art, ratchet type binders, such as the device disclosed in U.S. Pat. No. 9,102,259, are i) adapted to adjust a preliminary tension within small intervals defined by the pitch of a ratchet gear; ii) are the most expensive; and iii) are not well-suited for harsh environments. Turnbuckle type binders, such as the device disclosed in U.S. Pat. No. 8,491,237, are i) adapted to adjust force continuously without any intervals; ii) but require extra operational space for handle rotation in the plane perpendicular to the line of tension; and iii) also are not well-suited for harsh environments. Finally, lever type adjustable binders are i) adapted to operate in harsh environments; and ii) are preferred in applications wherein there is limited time for loading/unloading.
Lever load binders are typically used in tie-down applications for heavy equipment. The transport of heavy equipment, such as military, construction or other like equipment, is frequently accomplished over rails, on trucks, and/or on ships and barges. The heavy equipment is typically tied down to a flat bed of the vehicle so that the cargo does not move or oscillate during transport thereof.
Although the prior art has provided various improved designs of adjustable lever load binders (e.g., U.S. Pat. No. 7,913,363), and although each new design has provided certain additional benefits, today's adjustable lever load binders still have certain drawbacks. First, many prior art lever load binders lack the capability to readily make fine adjustments for accommodation of the length of the tiedown chain. As will be understood by those skilled in the art, it is often necessary to couple and decouple the tiedown chain from the lever load binder during cargo securement to determine the appropriate link of the tiedown chain for engagement with the binder. More particularly, if the tiedown chain is too tight, then the locking of the lever load binder may over stress the components of the tiedown assembly. If the tiedown chain is too loose, then the locking of lever load binder may not remove all of the slack from the tiedown chain. Thus, the mentioned installation process can be a time-consuming and intricate procedure. Often times, the necessary adjustment length to ensure proper loading is equal to or less than the length of a link of the tiedown chain. Because the orientation of the lever load binder is substantially fixed due to the connection of such binder to the transportation vehicle, it is generally necessary to adjust the length of the tiedown chain in increments of two links. In other words, because the adjacent links of the chain are oriented 90° from one another, attempting to adjusts the length of the tiedown chain by a single link can result in the twisting of the tiedown chain or of the lever load binder. Of course, any twisting of components in the tiedown assembly is undesirable, and should be avoided. Second, typical prior art lever load binders are designed as “over center binders”. The lever of an over center binder, when in the locked position, is located over a lever pivot point or a line of tension. Although the location of the lever at this position generates additional locking torque, it also requires the operator to overcome this additional torque (in addition to the friction resistance force) when rotating the lever in the opposite direction during release. Third, over center binders are more likely to experience handle kickback as the handle moves from the over center locked position through the tension line. Fourth, prior art lever load binders typically have a constant geometrical proportion between the length of the lever used to apply the locking force and the internal point where the force is delivered to tension the chain. In such a design, the amount of force required during the final moment of locking is significantly greater than the force expended up until that point because of the two shoulder design.
There is therefore a need in the art for a lever load binder which provides fine adjustments for accommodation of the length of the tiedown chain, and does so in a time sensitive manner and without twisting of the tiedown chain or lever load binder. There is a further need in the art for a lever load binder which increases the efficiency and safety of using the device.